Recently, the number of deaths due to cancer is increasing year by year. On the other hand, therapeutic means have been developed rapidly against cancers and therapeutic methods for some kinds of cancer have been established.
Especially, many kinds of anti cancer antibodies have been prepared and used as a therapeutic or diagnostic drug, since the publication of Kohler and Milstein about production of monoclonal antibodies [Kohler, G. and Milstein, C., Nature, 256, 495 (1975)]. These antibodies are used for antibody missile therapy in which antibody specifically binds to cancer cells and exclude or injured them without injuring normal tissues, and show some degree of success in the therapy of blood cancer such as leukemia or lymploma.
However, few effective preventive methods are available at present against metastatic cancers. Factors affecting cancer metastasis presumably include the cell molecule surface, cell skeleton, protease and so forth. Other factors so far reported to be involved in the metastatis of cancer cells have been clarified in detail, for example metastasis-promoting factors, there are the autocrine motility factor (AMF) [Proc. Natl. Acad. Sci. USA, 83, 3302-3306 (1986)] and the chemotactic factor [Igaku no Ayumi (Advances in Medicine). 150, 805-806 (1989)]. However, cancer matastasis involves a very complicated process and therefore before the whole picture thereof is far from clarified. Under the present conditions, the use of an in vitro experimental cancer metastasis model system is thought to be most efficient in developing an agent capable of inhibiting cancer metastasis. A method comprising counting cells passing a filter (Nucleopore) having uniform pores of 5-8 .mu.m in pore size using a chemotaxischamber is in wide use as such a system.
In the treatment of cancer, some effective therapeutic means have been established against specific kinds of cancer. However, the metastasis of cancer is difficult to prevent and at present no effective therapeutic means is available therefor.